Automatic switching device for electric phonographs



July 28, 1931. A. N. GOLDSMITH AUTOMATIC SWITCHING DEVICE FOR ELECTRIC RHONOGRAPHS Filed Aug. 26, 1925 srARn/va m/m/is .sW/m/ .sW/mw mm 25 a 26 35 27a 22 INVENTOR M Mean 70 claim MAI/0411) mm! 70 ALFRED GOLDSMITH 17 8 18 Will/70114276411) 19 820 Patented July 28, 1931 UNITED STATES PATENT OFFICE ALFRED N. GOLDSMITH, OF NEW YORK, N. Y., ASSIGNOR TO RADIO CORPORATION AMERICA, A CORPORATION OF DELAWARE AUTOMATIC SWITCHING DEVICE FOR ELECTRIC PHONOGRAPHS Application filed August 26, 1925. Serial No. 52,498.

This invention relates to the reproduction of music, speeches and other sounds. More specifically, it relates to what are known as electrical phonographs.

5 An electrical phonograph consists of an electrical pickup device or reproducer which is actuated by a needle resting in the record groove, and which produces an alternating or fluctuating current corresponding to the sound waves of the record, an audio frequency amplifier (either vacuum tube type or otherwise) and a loud speaker. The last two named elements may be a part of a radio receiver and therefore usable either for radio or phonograph purposes. This invention is covered by other applications filed by me on June 9th',-1925, Serial No. 35,853, and on June 12th, 1925, Serial No. 35,572. i Briefly my invention is, to arrange matte'rs so that in an electrical phonograph any of the mechanical acts which must in any case be performed to listen to a record may mechanically or electrically or both turn on the audio frequency amplifier in question and make any other required electrical changes; and the reversal of these acts may similarly automatically turn ofl" the audio frequency amplifier. Another object of my invention, additional to the preceding, in the case where the audio frequency amplifier of a radio receiver is used for electric phonograph purposes, is to have the acts which are necessary to start listening to the phonograph record also switch over internal connections in the radio receiver whereby its audio frequency amplifier is transferred from the radio connection to the electric phonograph connection.

There are then five causative acts necessary to listen to a phonograph record which are as follows: a i

turn table. This does not exist in all phonographs.

2. Opening the door in front of the grill from which the sound emerges. This does not exist in all phonographs.

3. Operating the turn table motor starting lever. This always exists either as a mechanical release or an electrical motor switch. I

hLowering the reproducer upon the, record. r 3

5. The starting of the motor governor which is used to hold the speed constant in either spring motor or electric motor driven phonographs. This governor has moving parts which assume a definite'spatial rela- '3 tionship when the turn table is rotating at the desired speed and a different spatial relationship when the turn table is rotating at a slower speed or is at rest. I i

There are three ways in which any of the five preceding acts may operate electrical switches. They are 1. By direct attachment of the switch in question to some portion of the above mentioned acting parts. Thus, for example, .a switch or a multiplicity of switches can be directly operated from the turn table motor starting lever. v t y 2. Thru a mechanical connection to a more distant switch. For example, the starting Q lever may be connected thru a long rod to a switch located under the radio panel and therefore directly coupled mechanically to the starting lever. V

3. .Thru an electrical relay controlled by a master contact or contacts on the acting part. Thus, the spring governor referred to above may have attached to it an electrical contact which is closed when the phonograph comes up to speed. A circuit 35 may therefore be shut which operates a powerful relay, which in turn, performs any desired switching operations.

There are two principal switching operations which might be controlled by any of I the five actsv classified above, operating in any of the three ways mentioned above.

1 These two switching operations are: 1. Lifting the lid which covers the record 1 1. Connecting an audio frequency amplifier, and any circuits associated therewith, to anelectrical phonograph reproducer and any circuits associated therewith; connecting or disconnecting a loud speaker and its associated circuits to said audio frequency amplifier (if desired); turning on an audio producer of the pl'ionograph.

frequency amplifier; or, briefly, making any receiver; connecting such audio frequency amplifier or a portion thereof to the electrical reproducer or a pick-up device of an electric phonograph. V

In the figures of the drawings, Fig. 1

is a diagram of my device and Fig. 2 is a table. These figures show one form of my device and the manner of operation thereof wherein the acting part is the starting lever, the method of control is thru a mechanical connection to a master switch, and the switching operations chosen are turi'iing on the audio frequency amplifierof a radio receiver and switching the input'terminals of such amplifier from connection to theradio detector plate circuit over to the electric re- 7 This is, of course, a special case of the invention.

1 Referring'more particularly to Fig. 1, 1

shows the detector tube as used in a familiar radio apparatus'together with its radio frequency amplifying tubes2 and its audio frequency amplifying tubes 3 coupled together by means of transformer coils l and 5. The

output of this radio set is cennected to the loud speaker 6 mounted in the cabinet 38 with an outlet through the grill 37 ordinarily protected by the door 35. The radio set is operated bymeans of a high potential battery 7 and a low potential battery 8 which is controlled by switch 36. This switch may be operated manually or by automatic vmeans such as the door 35 or other of the causative acts above enumerated, as desired.

On the turn table 14 of a phonograph arrangement is mounted the record 13 which is provided with an undulatory groove. An electrical reproducer 9 is so arranged as to follow this groove upon the rotation of the turn table about the axis 32. 16 is the starting lever for the phonograph to which is attached braking element 15 and switch ele- 1nents'25, 26, 27 and 28. The indicator 12 points to marks 11 or 10 depending upon which position is desired for indicating the apparatus to be operated.

The insulating shaft 29 is mounted to r0- tate about its axis 30, 31 and'in one position appliesthebrake 15 to the phonograph simultaneously making contact with 17, 18, 19

and 20. V In the other position, it releases the brake 1'5 and contacts with 21, 22, 23 and 24. Thus, it can be seen, in the position indicated in the figure, that the phonograph disk "will be stopped and connections will be made between the plate of the detector tube 1 to the primary of the transformer 4 through the contacts 25, 26 and 17, 18 to the high potential battery 7 and back to the detector tube thereby causing the desired oscillations in the outputcircuit from the last amplifiers 3 through the loud speaker 6 back througa thehigh'potential battery 7. Also the low potential battery will be applied to the amplifier tubes 3 as well as the i detector and radio frequency tubes 1 and 2 respectively. In this position both circuits 33 and 34- will be energized by the low potential battery 8.

Now when the lever 16 is thrown to indicate phonograph as atlO, the low poten tial circuit from the contacts 27 and 28 to the filament circuits 33 and 34; will be broken 'at 19 and 20 and the filament circuit 3% alone will beestablished by'the contacts 23 and 24. Also the output circuit of the detector tube 1 will be broken at 17 and 18 by contacts 25 26 and a new circuit 'will be established between the reproducer 9 through contacts 21 and22, contacts 25 and 26 t0 the primary winding of the input transformer for the audio frequency tubes 3 thereby reproducing in the" loud speaker 6.. the undulations of'the record 13. A simple and readily operated arrangementis there-1 by provided for operating either the radio or the phonograph at will.

I wish to be limited only to the perform- 'ance of any of the last two mentioned switchingoperations, thru any of the three means mentioned directly preceding, asa result of any of the five acts" classified at the a beginning of this description and by the following claims.: 2

1. The combination of a radio receiving set having a vacuum. tube radio frequency amplifier, a vacuum tube detector, anda vacuum] tube audio frequency amplifier, with an electrical phono raph pick-updevice, a rotatable table, a current source for 0 heating the filaments of said vacuum-tubes,

a brake to control the rotation of said table, and means operable bysaid brake to. connect said pick-up device to said audio frequency au'iplifier and simultaneouslyto disconnect #15 the current source for heating the cathodes of said radio frequency amplifier and detector, or alternativelyto' connect said radio frequency amplifier and detector to said audio frequency amplifier and simultane- W0 ously to connect the current sourcesfor heating the cathodes of the radio frequency amplifier and detector. q l

2. The combination of a radioreceiving set having a vacuum tube. radio frequency 222 amplifier, a vacuum tube detector, and. a vacuum tube audio frequency amplifier, with an electrical phonographxpickup device, a rotatabletable, acurrentxsourcefor heating the cathodes of said vacuum tubes, 1.

a brake to control the rotation of said table, a first pair of fixed contacts connected to the cathode heating circuits of all the vacuum tubes, a second pair of fixed contacts connected to the cathode heating circuit of the audio frequency amplifier only and a pair of contacts connected to said current source and movable with said brake into engagement with either of said pairs of fixed contacts, whereby selectively to energize said filament circuits.

3. A combined radio receiver and phonograph having a vacuum tube radio frequency amplifier, a vacuum tube detector, an electrical pick-up device, a rotatable table adapted to support a record to be played by said pick-up device, a vacuum tube audio frequency amplifier, a first pair of fixed contacts connected in the output circuit of the detector, a second pair of fixed contacts connected to the pick-up device, a pair of movable contacts connected to the input circuit of said audio frequency amplifier and selec-' tively movable into engagement with each of said pairs of fixed contacts whereby to connect either the output of the detector or of the pick-up device to said audio frequency amplifier, a brake device to control the rotation of said table, and means connecting said brake device and said movable contacts whereby the same may be moved together.

4. A radio-phonograph combination com prising an electric pick-up device, a rotatable turn table, brake mechanism for said turntable, radio receiving apparatus, said radio receiving apparatus including a plurality of thermionic space discharge devices at least one of which is an audio frequency amplifier adapted to amplify electrical variations from said electric pick-up device, cathode heating circuits for said space discharge devices, and means actuated by the operation of said brake mechanism for controlling the energization of the cathode heating circuits of other of said space discharge devices than said audio frequency amplifier.

ALFRED N. GOLDSMITH. 

